CISA and the FBI are warning that shared corporate services can undermine operational technology isolation before an incident ever tests the design. In joint guidance released July 28, the agencies said organizations may believe OT is separated from the enterprise while hidden dependencies still link those environments together.
The alert highlights a key weakness in many segmentation projects: mapping the network may not reveal every service that OT depends on. That means a system can look isolated on paper but still rely on common enterprise resources that reconnect it to the broader IT environment.
For healthcare organizations, the issue is especially important because clinical and facility OT may appear separate while still being tied back to centralized business systems. If those shared dependencies are overlooked, a cyber event affecting enterprise IT could still disrupt systems that leaders expected to be insulated.
The federal guidance shifts the focus from simple network boundaries to deeper dependency analysis. Instead of treating isolation as a diagramming or segmentation exercise alone, security teams are being told to examine the shared services that keep OT functioning and that may quietly defeat true separation.
